It is common to transport flowing gases, particularly natural gas, from an area of production to an area of consumption. The transmission of natural gas is usually accomplished by use of a pipeline through which the gas flows. It can be seen how the quantity, or volume of gas flowing through the pipeline must be determined so that the delivered amount is known.
Many types of flowmeters have been used to provide this monitoring function, including orifice meters, swirlmeters, vortexmeters meters and turbine flowmeters. Further, compensated turbine flowmeters are also known, for example, U.S. Pat. No. 3,176,514 to Foster shows a meter compensating system which inputs a pressure and temperature signal into a pressure/temperature to time converter (multivibrator) and then combines the converted signals with the output of a turbine flowmeter in a gating circuit. This combined signal is then output put to a pulse totalizer which may be a digital counter, or mechanical counter, when low frequency pulses are output. U.S. Pat. No. 3,537,312 to Moore shows pressure, temperature and turbine flowmeter inputs. The pressure and temperature signal voltages are compared with a ramp voltage and if the temperature voltage equals ramp voltage a pulse is fed to a gate circuit, thereby opening the gate. The flowmeter signals are allowed to pass when the gate circuit is open and are then fed into a counter and display. Cornforth (U.S. Pat. No. 4,390,956) is a gas flow volume corrector which utilizes temperature and pressure inputs, an uncorrected value for the volume of flowing gas, and a set of constants derived from base (temperature and pressure) conditions and gas content in a series of calculations to determine the supercompressibility factor and in turn a corrected volume. None of the aforementioned references provide a frequency signal usable in a variety of interfaces, such as remote terminal units (RTU) and personal, or system computers. Furthermore, these prior art references do not include any means for verifying the actual line parameters, i.e. raw temperature, pressure and actual volume flow rate values which can be used to confirm that the correct compensated volume is being output.